Question: Simplify the expression. $ (-7a^{7}-3a^{4}-7a) - ( 6a^{7}+6a^{5}-a^{4}) $
Solution: Distribute any negative signs. $(-7a^{7}-3a^{4}-7a) + (-6a^{7}-6a^{5}+a^{4})$ Since we are adding polynomials, we can simply remove the parentheses. $-7a^{7}-3a^{4}-7a - 6a^{7}-6a^{5}+a^{4}$ Identify like terms. $ - {7 a^7} - {3 a^4} - \color{#9D38BD}{7 a} - {6 a^7} - \color{#DF0030}{6 a^5} + { a^4} $ Combine like terms. $ { ( -7 -6 ) a^7} + \color{#DF0030}{ -6 a^5} + { a^4} + \color{#9D38BD}{ -7 a} $ Add the coefficients. $-13a^{7}-6a^{5}-2a^{4}-7a$